Development of the Fetal Heart & Circulation

Movement of fetal blood

Flows away from the placenta through the umbilical vein

Beginning of fetal heart formation

The angiogenic clusters combine and form two tubes with myocardial tissue.

Fetal heart formation week 5-6

The formation of the septum secundum takes place in the atria. By the end of the sixth week the septum secundum forms a flap that is the foramen ovale.

Fetal Heart: Fun Facts

The heart begins to form in week 3. It is the first recognizable organ. By week 8 the heart will be fully functional with all chambers, valves, and major vessels in place.

What layer forms the heart?

The mesoderm

Fetal heart formation end of week 8

The mitral and tricuspid valves are formed. The ventricular septum closes. Heart is almost complete.

Important note

The mothers lungs and liver provide most of the same functions in the same organs in the fetus/embryo

Fetal heart formation week 6

The pulmonary arteries form from the aorta.

Fetal heart formation day 22

The tubes continue to merge forming three structures; bulbous cordis, ventricular bulge, and the atrial bulge.

Fetal heart formation day 18

The two tubes fold into the thoracic cavity.

Fetal heart formation day 23-24

The ventricle buldge grows and starts process called "dextral looping." This causes the atrial bulge up into a superior position, this is called bulboventricular loop. As the ventricle continues to fold, the interventricular septum begins to form. This is the beginning of the division of the ventricles.

What are angiogenic cell clusters?

They are "blood islands" that supply nutrition to the embryo.

Fetal Blood Circulation

https://www.youtube.com/watch?v=-IRkisEtzsk